Drive fastener device

ABSTRACT

The present invention relates generally to improvements in staples and spikes and in methods for producing same. The invention as disclosed herein contemplates a novel staple or spike structure wherein the work engaging extremities of the staple or spike tines present chisel-like arcuate edges of limited extent at the convergence of longitudinal oppositely disposed swaged surfaces. Each tine extremity also present opposed longitudinal surfaces disposed at substantially 90* with respect to the converging swage surfaces, and terminate at opposite ends of a complemental arcuate or curved work engaging edge. The invention also contemplates a novel method of producing the above-mentioned structure by shearing and swaging the opposite extremities of a pre-determined length of metallic rod stock.

United States Patent [1 1 3,865 12/1894 Great Britain 85/30 in] 3,800,654 Larson Apr. 2, 1974 DRIVE FASTENER' DEVICE 9,961 3 1902 Great Britain 85/30 [75] Inventor: Charles 0'. Larson, Sterling, Ill. v

g i v Primary Exammer Marion Parsons, Jr. [73] Asslgneei C aS- 0- g, Attorney, Agent, or FirmOlson, Trexler, Wolters,

[22] Filed: Sept 1972 Bushnell & Fosse, Ltd. v

Related Application Dam The present invention relates generally to improve- [63] Continuation of Ser. No. 46,397, June 15, 1970, ments in staples and spikes and in methods for proabandoned. ducing same. The invention as disclosed herein con- 7 templates a novel staple or spike structure wherein the [52] US. Cl. .t 85/49, 85/30 work engaging extremities of the staple or spike tines [51] Int. Cl. Fl6b 15/00 present chisel-like atcuate edges of limited extent at vField of arch 85/49, 30, 31, 18 the convergence of longitudinal oppositely disposed swaged surfaces. Each tine extremity also present op- [56] 7 References Cited posed longitudinal surfaces disposed at substantially UNITED STATES'PATENTS 90 with respect to the converging swage surfaces, and 63 385' 4/1867 Harvey.... 35/49 terminate at opposite ends of a complementa] arcuate 6/1884 Hyslop I 85/30 or curved work engaging edge. The invention also 387,380 8/1888 Thayer 85/30 contemplates a novel method of producing the above- 550,795 12/1895 Markoe t 85/30 mentioned structure by shearing and swaging the op- ,0 6 3/ 1922 Overbu'rym; 85/ 0 posite extremities of a pre-determined length of metal- FOREIGN PATENTS 0R APPLICATIONS swck- 2 Claims, 22 Drawing Figures 1 DRIVE FASTENER DEVICE REFERENCE TO RELATED APPLICATION This application is a continuation of US. Pat. application Ser. No. 46,397, filed on June 15, 1970.

SUMMARY OF THE INVENTION It is a well-known fact that many of the staple and spike devices now available on the open market have structural deficiencies which render such devices difficult to properly drive in place. One of such deficiencies results from mis-alignment of the entering or work engaging extremities thereof. Such mis-alignment has a tendency to cause the tine totilt or cant when hammerplates the production of the above mentioned fastener devices having-such structural uniformity and correct ness at the point of initial penetration within a workpiece that the possibility of tilting or canting, as well as cracking of the workpiece, is reduced to a minimum.

To assure the'aforesaid uniformity and correctness in structural design, the present invention also contemplates improved, practical methods of producing such staples by practicing novel shearing and swaging steps, resulting in the formation of accurately positioned, curved chisel-like edge at the free extremity of each staple tine.

BRIEF DESCRIPTION OF THE DRAWINGS A The foregoing and otherobjects and advantages will be more apparent from the following detailed description when considered in connection with drawings wherein: v I

FIGLITisa side elevational'view of a length of metallic rod material of the type from which sections may be sheared to be formed into staples of thetypecontemplated by the present invention;

FIG. 2 is a view similar to FIG. 1, disclosing a section of predetermined length sheared from the rod material of FIG. 1; I I I FIG. 3 is an elevational view of the predetermined length of rod stock of FIG. 2, formed with oppositely disposed swaged surfaces converging into a chisel-like curved or arcuate edge. The swaging operation may occur before or after the predetermined length of stock of FIG. 2, has been bent into U-shape, and this U-shape I form is illustrated by dotted lines in FIG 3;

FIG. 4 is a side elevational view of the U-shaped staple after initial swaging, dotted lines indicating ultimate shape of the staple tines;

FIG. 5 is an enlarged illustration of the swaged side of one of the stapled tines as viewed in FIG. 4, with dotted lines indicating the opposite elongated sections of the swaged sides which have been removed as for example by shearing;

FIG. 6 is a view similar to FIG. 5, more clearly to illustrate the curved or. arcuate chisel-like edge formed by the converging swaged sides of the tines;

FIG. 7 is a side elevational view similar to FIG. 4, after opposed sections of the swaged surfaces have been removed so as to provide converging side surfaces disposed at substantially with respect to the previously swaged surfaces;

FIG. 8 is an enlarged framentary elevational view of the staple tine as viewed from the right of FIG. 7;

FIG. 9 discloses a predetermined length of metallic rod material in association with swaging dies employed to impart a substantially semi-spherical shape to each end of the rod;

FIG. 10 discloses the metallic rod of FIG. 9, bent into U-shape;

FIG. 11 discloses the U-shaped member of FIG. 10 swaged on opposite sides of each staple tine to provide surfaces which converge to provide chisel-like curved edges;

FIG. 12 is a diagrammatic illustration of the manner in which swaging dies may be employed to swage the opposite sides of the staple tines;

FIG. 13 discloses one of the staple tines in association with shearing dies employed to remove opposite elongated sections of the previously swaged surfaces;

' FIG. 14 is a perspective view of the arrangement shown in FIG. 13, more clearly to illustrate the opposite elongate sections sheared from each staple leg or tine.

FIG. 15 is a perspective view of a staple type fastener before the opposite extremities thereof have been swaged;

FIG. 16 is'an elevational view of the staple device of FIG. 15, after opposite sides'of the tines thereof have been acted upon by swaging dies; I A

FIG. 17 is a vertical, sectional view taken substantially along the line 17-17 of FIG. 16, the staple tine being shown in elevation;

FIG. 18 is a view similar to FIG. 16, disclosing the staple tines after sections thereof have been sheared away so as to present oppositely disposed locking spurs; FIG. 19 is a detailed fragmentary perspectiveview of one of the tines, more clearly to illustrate the chisel-like shape of the work engaging extremity of a tine;

FIG. 20 is a perspective view of a spike device having the entering extremity thereof shaped to conform with the entering extremities of the staple device shown in FIG. 15;

FIG. 21 discloses the spike device of FIG. 20, after opposite sides of the entering portion thereof have beensubjected to swaging dies; and,

FIG. 22 is a vertical sectional view taken substantially along the line 22-22 of FIG. 1, the spike being shown in elevation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

In the production of the staple 16 a predetermined or given section of metallic rod material is severed from the length of the stock shown in FIG. 1. This severance results from shearing the stock in a direction substantially normal to the rod or stock axis. The opposite extremities of the severed length or section of rod stock may now be swaged by the application of suitable swaging dies to the opposite sides of the rod extremities. This swaging operation may occur before or after the severed stock has been formed into a U-shape as illustrated by the dotted lines in FIG. 3, and as shown by the solid lines in FIG. 4. It is of importance to note that the swaging operation is such as to produce a discreet curvature or arcuate shape in a chisel-like edge 24, at the extremity of each tine 22. Thus, by swaging opposed I and in FIG. 7, the completed staple illustrates the shape of the staple tines after the sections 26 have been sheared from the central tine body. It will be noted that removal of the oppositely disposed longitudinal peripheral sections 26 provides a pair of oppositely disposed converging surfaces 28, disposed at substantially 90 with respect to the above-mentioned swaged surfaces. In fact, the converging extremities of the surfaces 28 terminate at opposite ends of the curved chisel-like edges 24. In other words, the planes coincident with the surfaces 28 intersect the curved or arcuate chisel-like edges. This resulting curved edge of limited extent greatly facilitates the ease with which the completed staple may be driven into a workpiece.

From the foregoing it will be apparent that a staple device constructed in accordance with the teachings of the present invention provides swaged opposed sides of each tine which converge into chisel-like arcuate or curved work entering edges of limited extent, positioned within a common plane coincident with the plane which includes a central longitudinal axes of the staple tines. This plane is indicated by the dot and dash line 30, of FIG. 8. Also the oppositely disposed surfaces 28 converge toward a central longitudinal plane designated by the dot and dash line 32 in FIGS. 5, 6 and 7. The uniform convergence of the swaged surfaces toward the central plane 30, and the uniformity in convergence of the longitudinal opposed surfaces 28 toward the central planes 32, together with the provision of the curved or arcuate chisel-like edge 24 of limited extent reduces to a minimum the tendency for the staple to tilt or cant when driven into a workpiece. Also the tendency for a workpiece to crack or split is substantially eliminated.

In FIGS. 9-14 inclusive, a slightly modified method of producing'applicants improved staples in shown. The only significant difference in this method from the previously described method is in forming, as by swaging, the extremities of the predetermined length of rod material from which the staple is to be formed. Thus, in FIG. 9, the opposite extremities of the rod section of given length is shown in association with suitable swaging dies 34, which when applied to the opposite extremities of the rod will form rod extremities 36 which are arcuate or curved in longitudinal section.

The staplestructure of FIGS. 10 to 14 inclusive, designated generally by the numeral 16a, has a bight portion 18a, and leg or tine portions 20a. Structural features of the staple 16a, corresponding with previously described structural details are indicated by similar numerals bearing the suffix a. FIG. 12 discloses a pair of swaging dies 38 which may be employed to swage opposite longitudinal sides of the staple tines to form the chisel-like edges 24a, and in FIG. 13, a pair of dies 40 are shown which may be employed to shear oppositely disposed longitudinal sections 26a and thus provide each tine with a pair of converging surfaces 28a, terminating at opposite extremities of the curved chisel-like edge 24a of limited extent. By forming curved tine extremities before lateral swaging thereof, a more pronounced or distinct curvature of the work engaging edge is assured. Thus the discreet chisel-like curved work engaging edges greatly facilitate the ease with which the fastener tines may be driven into a workpiece.

In FIGS. 15-19 inclusive, a still further modified form of fastening device is disclosed representing another embodiment contemplated by the present invention. FIG. 15 discloses a partially formed drive fastener or staple similar to structures shown in FIG. 10. The device of FIG. 15, is designated generally by the numeral 16b. This structure includes a bight portion 18b, and a pair of spaced tine portions or sections 20b having tip portions 36b. FIG. 16 discloses the device 16b after swaging dies 38b have been applied to the opposite sides of the entering extremities 22b of the tines 20b. Note that this results in the formation of curved or arcuate chisel-like edges 24b similar to the previously described curved work engaging edges 24a.

Referring now to FIG. 18, it will be seen that suitable shearing dies 40b may be employed to shear or cut away oppositely disposed elongate side sections 26b of each tine extremity 22b. In so doing oppositely disposed spurs or locking protuberances 42 are formed. Thus the drive fastener device 16b is not only provided with curved chisel-like entering edges 24b, but also with the locking spurs 42 which serve to increase resistance to forces tending to withdraw the fastener from the workpiece into which it has been driven.

A still further modified fastening device contemplated by the present invention is disclosed in FIGS. 20-22 inclusive. This fastener is in the form of a spike designated generally by the numeral 16c. This spike 16c has a body portion 200 and an entering section 220. The entering tip 36c of the spike is formed or swaged similarly to the previously described entering curved tips 36b of the staple device 16b. The entering extremity of the spike 16c is swaged and sheared in a manner similar to the previously described method of forming the chisel-like edges and spurs 42. Structural details of the spike 16c corresponding with the previously described structure in FIGS. 1519 inclusive, are given corresponding numerals bearing the suffix c. It will suffice to say the spike 16c incorporates a curved or arcuate chisel-like work engaging edge 240 as well as locking spurs 42c. Dies 38c function to swage opposite sides of the entering extremity of the spike, and dies 40c function to shear away oppositely disposed elongate sections 26c.

From the foregoing it will be apparent that in practicing the novel and practical methods contemplated by the present invention, the cost of producing structurally uniform staples and spikes of the aforesaid novel design is greatly reduced. Also the fastener structures resulting from the practice of such methods are greatly improved over many of the fasteners now available on the .open market. Each tine is provided with chisel-like arcuate work engaging edges of limited extent positioned within a common plane coincident with the plane which includes a central longitudinal axes of the staple tines. By swaging the opposite sides of the tines 'to form the chisel-like cutting edge along the line of intersection of such surfaces, the hardness and toughness of thematerial of the tines is materially enhanced. The provision of the oppositely disposed locking spurs materially increases the resistance to forces tending to loosen the fastener.

I claim:

1. A staple device comprising: a U-shaped length of metallic rod material presenting a pair of spaced tines; each said tine including; a first pair of elongate symmetrical longitudinal side surfaces, each said first side surface defining a plane, said planes tapering inwardly arcuate chisel-like work-entering edge of limited extent positioned within a plane which includes the central longitudinal axis of said tine; and a second pair of elongate symmetrical opposed longitudinal side surfaces disposed at substantially with respect to said firstmentioned pair of side surfaces, each said second side surface defining a plane, said planes tapering inwardly and converging from the rod periphery toward the central longitudinal axis of the associated tine, second side surfaces being disposed such that the planes defined thereby intersect said central longitudinal axis at a location disposed axially from said work-entering edge along said central axis, such that said second pair of side surfaces intersect said work-entering edge at spaced-locations to define the extent of said edge.

2. A staple device as defined in claim 1, wherein said converging side surfaces are swage-hardened. 

1. A staple device coMprising: a U-shaped length of metallic rod material presenting a pair of spaced tines; each said tine including; a first pair of elongate symmetrical longitudinal side surfaces, each said first side surface defining a plane, said planes tapering inwardly and converging from the rod periphery toward the central longitudinal axis of the associated tine and intersecting proximate the work entering edge of the tine, such that said first pair of side surfaces terminate in an arcuate chisel-like work-entering edge of limited extent positioned within a plane which includes the central longitudinal axis of said tine; and a second pair of elongate symmetrical opposed longitudinal side surfaces disposed at substantially 90* with respect to said first-mentioned pair of side surfaces, each said second side surface defining a plane, said planes tapering inwardly and converging from the rod periphery toward the central longitudinal axis of the associated tine, second side surfaces being disposed such that the planes defined thereby intersect said central longitudinal axis at a location disposed axially from said work-entering edge along said central axis, such that said second pair of side surfaces intersect said work-entering edge at spaced locations to define the extent of said edge.
 2. A staple device as defined in claim 1, wherein said converging side surfaces are swage-hardened. 